lua: add an SCPacketTimestamp function

The SCPacketTimestamp function returns packet timestamps as 2 real
numbers (seconds & microseconds).

Example:

  local sec, usec = SCPacketTimestamp()

Signed-off-by: Nicolas Thill <ntl@p1sec.com>

src/util-lua-common.c

@@ -158,6 +158,21 @@ static int LuaCallbackPacketPayload(lua_State *luastate)
     return LuaCallbackPacketPayloadPushToStackFromPacket(luastate, p);
 }
 
+/** \internal
+ *  \brief fill lua stack with packet timestamp
+ *  \param luastate the lua state
+ *  \param p packet
+ *  \retval cnt number of data items placed on the stack
+ *
+ *  Places: seconds (number), microseconds (number)
+ */
+static int LuaCallbackTimestampPushToStack(lua_State *luastate, const struct timeval *ts)
+{
+    lua_pushnumber(luastate, (double)ts->tv_sec);
+    lua_pushnumber(luastate, (double)ts->tv_usec);
+    return 2;
+}
+
 /** \internal
  *  \brief fill lua stack with header info
  *  \param luastate the lua state
@@ -174,6 +189,19 @@ static int LuaCallbackTimeStringPushToStackFromPacket(lua_State *luastate, const
     return 1;
 }
 
+/** \internal
+ *  \brief Wrapper for getting packet timestamp (as numbers) into a lua script
+ *  \retval cnt number of items placed on the stack
+ */
+static int LuaCallbackPacketTimestamp(lua_State *luastate)
+{
+    const Packet *p = LuaStateGetPacket(luastate);
+    if (p == NULL)
+        return LuaCallbackError(luastate, "internal error: no packet");
+
+    return LuaCallbackTimestampPushToStack(luastate, &p->ts);
+}
+
 /** \internal
  *  \brief Wrapper for getting tuple info into a lua script
  *  \retval cnt number of items placed on the stack
@@ -719,6 +747,8 @@ int LuaRegisterFunctions(lua_State *luastate)
     /* registration of the callbacks */
     lua_pushcfunction(luastate, LuaCallbackPacketPayload);
     lua_setglobal(luastate, "SCPacketPayload");
+    lua_pushcfunction(luastate, LuaCallbackPacketTimestamp);
+    lua_setglobal(luastate, "SCPacketTimestamp");
     lua_pushcfunction(luastate, LuaCallbackPacketTimeString);
     lua_setglobal(luastate, "SCPacketTimeString");
     lua_pushcfunction(luastate, LuaCallbackTuple);